The field of communications has become increasingly important in today's society. In particular, the ability to quickly and effectively interact with an individual (through any suitable communications media) presents a significant obstacle for component manufacturers, system designers, and network operators. This obstacle is made even more difficult due to the plethora of diverse communication technologies (e.g. Instant Messaging, cellular communications, simple voice sessions, etc.) that exist in the current marketplace.
Camp-on is a common feature in many systems today, such as Private Branch exchanges (PBXs). This feature allows a caller who calls an individual whose line is busy to have her phone connected to the called party when the called party completes his call. When the called party hangs up, the system rings and/or alerts the called party of the caller's call. Some instant messaging (IM) systems allow users to transmit instant messages to users who are not logged in. Some IM systems also notify users whenever a “buddy” on a particular buddy list logs in or out.
Problems arise when the camping party needs to go to a meeting while the called party has not yet freed up. With some systems, the only available solution for the camping party is to revoke the camp-on request. If the calling party fails to revoke the camp-on request, the system attempts to connect the called party with the office of the calling party and gets a ring-no answer from the calling party.